Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!
-or
suffix. agental suffix
glastrin
adjective. marble
glast
noun. marble
A noun appearing as G. glast “marble” in the Gnomish Lexicon of the 1910s (GL/39), probably derived from ᴱ✶ʒalast- like its cognate ᴱQ. alas (alast-) “marble” in the contemporaneous Qenya Lexicon (QL/30).
Neo-Sindarin: I think this word may be salvageable in Neo-Sindarin as ᴺS. glast, reconceived as a derivative of ᴹ√GALAS “joy, be glad”, perhaps from ᴺ✶galast- originally with the sense “thing pleasant to touch”.
fafli
noun. bladder
A noun appearing as G. fafli “a bladder” in the Gnomish Lexicon of the 1910s, an elaboration of G. faf- “puff, blow” (GL/33).
Neo-Sindarin: I would adapt this word as ᴺS. faul “bladder” from ᴺS. faw- “puff, blow”, likely with the original sense “inflated thing”. This mirrors the etymology of English “bladder”, which is also derived from an ancient verb meaning “to blow”.
aithog
adjective. thorny
dos
adverb. when
glan
adjective. pure, clean, (originally) bright
-(r)on
suffix. agental suffix
-og
suffix. agental suffix
-os
suffix. masculine suffix
-weg
suffix. masculine suffix
a
preposition. from
amil
noun. mother
antha-
verb. to give
grann
noun. strong place, fort; walled town, city
mab(a)
noun. mother
math
noun. dusk
ôn
noun. gift
(m)ami
noun. mummy
cwelm
noun. dusk
gwesta-
verb. to entertain
nigrin
adjective. stealthy
-ir
suffix. agental suffix
amaith
noun. mother
ami
noun. mummy
aura-nûmin
proper name. Sunset
grand
noun. town
mabir
noun. mother
nalos·aura
proper name. Sunset
nanwin
noun. mother
nân
noun. mother
o
preposition. from
An adjective appearing as G. glastrin “marble” in the Gnomish Lexicon of the 1910s, an adjectival form of G. glast (GL/39).
Neo-Sindarin: If adapted to Neo-Sindarin, I think this word would become ᴺS. glathren: compare S. othrond from S. ost + S. rond.